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Solar TV Remote 


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Solar TV Remote 

Written By: Paul Spinrad 


Hobby knifed) 

Lighter (1) 
or heat gun. 

Multimeter (1) 

Pliers (1) 

Scissors (1) 

Screwdriver (1) 

Soldering iron and solder (1) 

Tweezers (1) 

Wire cutter/stripper (1) 


• Remote control (1) 

that uses two 1.5V batteries or one 3V 

• Batteries (1) 

size and number to replace the remote's 

• Solar cell (1) 
from RadioShack. 

• Wire Insulated (1) 
from RadioShack. 

• Diode (1) 

from RadioShack. 

• Packing tape (1) 

• Velcro tape (6") 

• Heat-shrink tubing, multicolor 
assortment (1) 

from RadioShack. 


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Page 1 of 9 

Solar TV Remote 

Powering a TV remote with the sun means you won't have to buy batteries every six months 
to surf from your sofa. Low-voltage devices that use power only occasionally, like remotes, 
are good candidates for a solar-powered trickle-charge. Here's how we modded our remote 
to live off of the sun, using rechargeable batteries connected in parallel with a small solar 
cell and a diode to keep any power from trickling back out. 

Check out more Weekend Projects . 





The 6V solar cell module consists of a hard plastic case with two 3V solar cells connected 
in series inside. To charge our 3V remote, we'll disconnect these 3V cells and rewire them 
in parallel rather than in series. 

Use a small slotted screwdriver to pry the clear cover off of the case. 

Use pliers to bend away the rim of the case and breaking it off all of the way around. 

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Solar TV Remote 

Use a hobby knife to cut the three thin copper wires that connect the solar cells, the one 
running between the cells and the one going to each to the red (+) and black (-) leads. 

Mark with tape or otherwise note which lead runs to (+) and which runs to (-). You will 
need to know this later. 

Leave some length of wire where possible for soldering. 

Use heavy-duty scissors to cut out the plastic backing behind each solar cell. 

The bare solar cells are brittle silicon and they break or chip easily. As you cut the 
plastic, avoid bending it behind the cells or scraping against the cells with the 

If you look closely at the sides of the cells, you will see that they consist of six thin 
strips bonded together back-to-front and offset, like a staircase. Each layer 
contributes about 1/2V, and so the 6 "steps" stacked together generate a combined 3V. 

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Solar TV Remote 

Cut four lengths of 30-gauge insulated wire, and strip the ends. The wires should be long 
enough to reach from the battery contacts inside the remote's battery compartment out to 
the back of the remote where you will mount the cells. It's a good idea to cut the wires at 
least as long as the remote itself. 

Solder one wire to each of the thin copper wires attached to the solar cells. The wires from 
between the cells are short, which can make connecting to them a challenge. Have 
patience; this is the most difficult part of the project. After this, you're home free. 

A good way of soldering two thin wires together is to use pliers or tweezers to fold a little 
hook at the end of each, then loop the two hooks together and solder the joint. 

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Page 4 of 9 

Solar TV Remote 

• Clip any extra copper wire length from the solar cells. 

• Cut short lengths of 1/8" heat shrink tubing and slide them over the solder connections 

• Use a pocket lighter or heat gun to shrink the tubing over the joints. 

• If you use a lighter, hold the flame just above the heatshrink tubing, not below. 

Happiness is... learning that the pocket lighter your teenager has is only for 
shrinking heatshrink tubing in electronics projects. 

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Page 5 of 9 

Solar TV Remote 

Disassemble your remote enough to let you access the wire or metal spring contacts in 
the battery compartment, (+) and (-). With the TiVo remote shown here, this required 
removing the printed circuit board. 

Find a good place to connect the diode to the (+) battery contact, where it won't get in the 
way of reassembling the remote. Here, the diode had room alongside one of the batteries. 

Use a knife to cut away any plastic needed to clear a path for the diode to connect to the 
(+) battery contact. 

Trim the lead on the diode's cathode (-) side, marked with a stripe, and solder it to the (+) 
battery contact. 

A diode is a component that only lets electricity run through it in one direction only, Jf^ 
from its anode (+) to its cathode (-). This project uses one to ensure that solar cells t * I 
will charge the batteries, but that the batteries cannot discharge (lose power) through the 

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Solar TV Remote 

Step 6 — Package up the Cells 

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With clean hands, cut a strip of clear packing tape longer than both solar cells laid end-to- 
end, and lay it down sticky side up. 

Carefully place the solar cells down on the tape, centered end-to-end. Orient them such 
that wires that had originally connected to the red (+) and black (-) wires are diagonally 
opposite each other. 

Gently bend and route the four wires together so that they run off of the tape in two pairs, 
(+) and (-) . 

Each cell has a (+) and (-) lead, so the lead opposite the red-connected wire is (-) 
and the lead opposite the black-connected wire is (+). 

Cover the cells with a second strip of packing tape aligned sticky-side down over the first. 
Smooth down and squeeze the tape together to laminate the cells and wires neatly. 

Trim the tape around the cells with scissors, and twist the wire pairs together. 

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Solar TV Remote 

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Route the wire pairs to the remote's battery contacts the way they would go with the 
remote reassembled. With the TiVo remote, this meant threading them through the battery 
compartment cover opening in the bottom half of the remote's plastic case. 

Twist together the stripped ends of the (-) wire pair and solder it to the (-) battery contact. 

Twist together the stripped ends of the (+) wire pair and solder it to the free end of the 


• Use a knife to cut a notch in the remote case, just large enough to let the wire pairs exit 

• Use scissors to trim the tape around the cells. 

• Cut two Velcro tape pairs. Stick one side on the backs of the solar cells and the other side 
aligned on the back of the remote. 

• The Velcro lets you detach the solar panels in order to access the battery compartment 
and to position them directly facing the sun, for maximum charging. 

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Solar TV Remote 


Jk 11 

• Finally, load your rechargeable batteries. A typical remote will take 4-5 hours to charge its 
batteries fully in sunlight, but it never gets low as we leave it by the window. 

• As a build alternative, you can use a 3V flexible film solar cell from a specialty electronics 
supplier, instead of hard silicon solar cells. 

• Based on a project by Sparkle Labs. 

This document was last generated on 201 2-1 1 -03 04:1 2:06 AM. 

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